Conventionally, a fluorescent tube used in a backlight of the type includes a lamp formed of a glass tube and a Dumet wire led out from an electrode of the lamp.
As a connector used for connection of the conventional fluorescent tube, there are known connectors shown in Patent Documents 1 and 2.
A lamp connecting member (connector) disclosed in Patent Document 1 comprises a contact fixed to a frame. The contact comprises a generally-H-shaped planar electrode portion, a hole-shaped electrode portion formed at the center, arc-shaped electrode portions formed on opposite sides thereof, and a pair of arms connected to the arc-shaped electrode portions and bent to extend downward, respectively. The pair of arms have middle portions which are first narrow-spaced from each other and then formed into arc shapes. Thus, between the middle portions of the pair of arms, a circular space is formed as a lamp holding portion. Further, the arms have end portions opened from each other.
A cylindrical-shaped input terminal of the lamp, for example, a Dumet wire can be fitted to the lamp holding portion through the end portions of the pair of arms, which are opened from each other. When the input terminal of the lamp is removed, the input terminal can easily be removed by applying a force so that the fluorescent lamp is separated from the lamp connecting member. Thus, the lamp connecting member has a structure which allows the lamp to be easily fitted to and removed from the lamp connecting member.
In the connector shown in Patent Document 2, a fluorescent tube has a Dumet wire having an end formed into a spherical shape. The fluorescent tube is fixed to a lamp holder and supplied with a power supply voltage from the outside via the lamp holder to emit light. The lamp holder includes a power supply member for applying a power supply voltage to the fluorescent tube. The power supply member has a power supply terminal to be connected to the Dumet wire of the fluorescent tube. The power supply terminal has a ring shape opened at one side. By a spherical portion of the Dumet wire, the fluorescent tube is prevented from being removed from the power supply terminal in a direction along the length of the lamp.
However, the connector shown in Patent Document 2 requires a parts cost for a holder cap and a coupling plate. Further, after insertion of the lamp (CCFL tube), many-hours are required for operations of fitting the holder cap of the connector in order to ensure a contact force and of inserting the connector into the coupling plate and fixing the coupling plate to a sheet metal.
It is assumed that a θ error occurs during mounting of the connector and during fixing of a substrate. In this event, because a connecting portion is formed of the Dumet wire, a glass portion at a base of the Dumet wire 53 is directly loaded. This may possibly cause glass breakage.
Further, when the lamp is replaced, removal of the lamp becomes difficult and, therefore, it is inevitable to replace other parts also.
Furthermore, in Patent Document 2, a cap is embedded to be forcibly contacted with a contact. With this structure, a parts cost for the cap and an operation of fitting the cap are added.
In a connector shown in Patent Document 3, a cap-like ferrule is fitted to each of opposite ends of a W-shaped fluorescent tube. Walls of the fluorescent tube to which the ferrules are fitted are fixed with a silicone adhesive. Dumet wires as both terminals of the fluorescent tube are led out through the ferrules and then soldered to outer surfaces of the ferrules.
The fluorescent tube is held by a reflecting plate and contacts as a holding member. The contacts of the same shape are arranged, one on a high-voltage side of the fluorescent tube and the other on a ground side thereof. Each of the contacts has a pair of flanges of the same shape, which have a spring characteristic so that the ferrule formed at each of the opposite ends of the fluorescent tube is sandwiched and held on both sides in a direction orthogonal to a longitudinal direction of the fluorescent tube. Each of the contacts has an additional pair of flanges which protrude toward a side opposite to the above-mentioned flanges so as to face each other in the longitudinal direction of the fluorescent tube and each of which is provided with a leaf spring extending from its end in an oblique direction to prevent removal. The additional pair of flanges are inserted into two parallel elongate holes, respectively, which are formed in a backlight substrate.
In the connector in Patent Document 3, for the purpose of fixing the contact to the substrate, it is required to insert a part of the contact into the substrate and to perform soldering. Accordingly, correction of a positioning error between the substrate and the fluorescent tube is difficult. In addition, designing and assembling processes are difficult.
Further, after a lamp of the fluorescent tube is inserted into the ferrule and fixed thereto with the adhesive and the Dumet wire is bonded to the ferrule, it is required to bend the Dumet wire which is led out and to solder the Dumet wire to the ferrule. This process requires many-hours, resulting in a high cost.    Patent Document 1: JP-A-2004-294592    Patent Document 2: JP-A-2006-344602    Patent Document 3: JP-A-2000-123604